Sinuous font arrangement for a printing means

ABSTRACT

A font wheel having a plurality of character types arranged in a sinuous pattern is mounted for continuous rotation about its axis and for intermittent translation along its axis adjacent a sheet of paper on which selected characters are to be printed in a row along the axial direction of translation. A one-revolution selectively operated clutch connects a motive power source to a drive screw for intermittently translating the font wheel along its rotation axis. A print hammer disposed behind the paper travels axially with the font wheel and is driven toward the paper and font wheel at selective times to cause printing of selected characters in response to input data and font wheel position signals.

United States Patent Primary Examiner-Robert E1 Pulfrey AIImm-y: Palm 1!. l Stille -Anger,('lmrlm1L Lepchinsky,Rv

l'cuy Slupnmn and Jay M. (."nntor ABSTRACT: A font wheel having a plurality of character types arranged in a sinuous pattern is mounted for continuous rotation about its axis and for intermittent translation along its axis adjacent a sheet of paper on which selected characters are to be printed in a row along the axial direction of translation A one-revolution selectively operated clutch connects a mo tive power source to a drive screw for intermittently translating the font wheel along its rotation axis. A print hammer disposed behind the paper travels axially with the font wheel and is driven toward the paper and font wheel at selective times to cause printing of selected characters in response to input data and font wheel position signals.

[72] Inventor George E. Comstock Danville, Calif.

21 Appl. No. 820,408 [22] Filed Apr. 30, 1969 [45] Patented Aug. 17, 1971 [73] Assignee The Singer Company [74] CINHHIR: IFUNI AllllANHIi/VHLNI FUN A HUNTING MEANS 9 Claims, 4 Drawing Figs.

52 us. Cl .L 197 49, 101/93 C [51] Int. Cl B4lj H32 [50] Field of Search 197/49, 55, 18; 101/93 C [56] References Cited UNITED STATES PATENTS 1,405,722 2/1922 Siepmann et al. 197/47 2,843,243 7/1958 Masterson 197/19 2,926,602 3/1960 MacDonald et a1. 101/93 3,167,166 1/1965 Schiebeler 197/1 INPUT CHARACTER CODE FROM DATA SOURCE H111 COUNTER CARRIAGE RETURN CONTROL REGIfiTER PATENTEI] AUG 1 715m 3, 599.772

SHEET 1 0F 2 52 5b INPUT CHARACTER CODE 70 74 FROM DATA SOURCE 1 CLUTCH CONTROL CARRIAGE RETURN CONTROL INVENTOR.

4b fieorge 3 @omsrock (ANGULAR FOR SCREW PATENTEBAUBITBT! 3,599,772

saw 2 UF 2 MEMBER, LINEAR so I I FOR-CARRIAGE 25+ I AND FONT WHEEL TRANSLATION) I 0 I a I 90 150 mo zoo L+(0NE OPERATION mm) SPACING, Y UNIT COLUMN 7 I I I (LATERAL I I 0F FONT WHEEL 0 AND cARRIAeE) 5 T 25 T I l DISPLACEMENT 75 l l I l I l I I I I a l I270 I e (oNE oPERATIoNcYcLE) SINUOUS FONT ARRANGEMENT FOR A PRINTING MEANS BACKGROUND, FIELD OF INVENTION This invention pertains to a high-speed printing system and more particularly concerns a font wheel for use in a constant character spacing printing system which receives data asynchronously.

BACKGROUND, PRIOR ART Printing devices responsive to input data are useful in the mechanical and electronic data processing art as a means for providing permanent, easily readable records of data that is, has been, or is to be operated upon by the data processing mechanism.

With the advent of electronic data processors, or calculators, and high-speed electrical data signal generation and transmission, as found, for example, in high-speed paper tape and magnetic tape handling systems, and remote terminal devices, there has been a demand for devices which can transform electrical signal or codes into permanent meaningful human-readable form at very rapid rates. One form of device which is directed toward achieving these objectives is a highspeed printer that incorporates a font wheel having a plurality of character types arranged about its periphery in a one-turn helix pattern. The font wheel is continuously rotated about its axis, which axis is disposed parallel with the direction of the line or row area of a paper sheet on which printing is to occur. While the font wheel is continuously rotated about its axis, it is translated or moved axially along its axis in such a manner that for each one revolution of the font wheel, each character type is brought into printing position adjacent the same spot or location on the paper that is to receive a character impression (or no character impression in the event that a space is to appear at such location in the completed line). The translation of the font wheel axially along its axis is best achieved by means of a screw having a thread whose pitch is equal to the pitch of the helix pattern of the character types on the font wheel. One example of such a translating mechanism is shown and described in detail in U.S. Pat. No. 3,356,199 for Printer Having Type Disk Rotatable in a Plane Parallel to the Printing Line," by L. P. Robinson, issued Dec. 5, 1967 and assigned to the same assignee as the present application. Another example is shown in US. application Ser. No. 650,501, filed June 30, 1967 by A. F. Marion et al. for Inking Device now U.S. Pat. No. 3,526,309 issued Sept. 1, 1970 and assigned to the same assigne'e as the present invention.

In the prior art, high-speed, on-the-fly printers having a continuously rotated, and continuously translated font wheel with character types arranged in one-turn pure helical pattern, each of the characters printed in adjacent columns or locations on the paper inherently, are spaced apart equally from each other. For example, each letter in a word is spaced from adjacent letters by equal amounts as measured from lettercenter to letter-center. The same is true when printing a succession of numerals forming a multidigit number.

With the characters arranged in a continuous single turn pure helical pattern, input data must be supplied to the printing mechanism in synchronism with translational movement of the font wheel along its rotation axis. In other words, the data must be available at regular recurring time intervals.

However, in certain types of printing devices, the input data is not available at precise regular intervals. For example, in a manually operable keyboard, such as a typewriter, actuation of the keys ofa human operator occurs in highly irregular time sequence, and thus coded data representative of the character keys struck manually is furnished in an irregular or asynchronous manner.

Therefore, some means must be provided for utilizing the advantages of the helical font arrangements on a continuously rotated font wheel in a printing device wherein input data is only available in an asynchronous manner.

SUMMARY The present invention is achieved, in one embodiment, by providing a continuously rotatable but intermittently translatable font wheel having character types disposed thereon in a distorted arrangement; i.e., the character types extend in a sinuous arrangement.

A one-revolution clutch intermittently, when desired, couples a source of continuously energized rotative power to a helically grooved font wheel advancing means for spacing or translating the font wheel to the next adjacent printing location.

However, since the velocity of the print wheel is continuous in the angular direction, but varies in the lateral direction as it is accelerated and decelerated, the character types are arranged in a sinuous pattern about the circumference of the type wheel to compensate for the difference in lateral velocity and thus take advantage of a continuously rotatably, laterally moving font wheel in a printing apparatus wherein input data is available asynchronously.

It is therefore an object of the present invention to provide an improved printing apparatus.

Yet another object of the present invention is to provide an improved font wheel for an on-the-fly asynchronously operated printer.

The features of novelty that are considered characteristic of this invention are set forth with particularity in the appended claims. The organization and method of operation of the invention may best be understood from the following description when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a combined mechanical and electrical control illustration showing in simplified form a printer system of the present invention;

FIG. 2 is an illustration demonstrating the arrangement of character types on a font wheel according to the present invention;

FIG. 3 is an illustration of a typical lateral velocity graph or waveform of the font wheel of the present invention; and

FIG. 4 is an illustration demonstrating the lateral movement or displacement of the font wheel of the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 1, there is shown a high-speed, on-the-fly, asynchronous printing system which incorporates a mechanical unit 10, plus electrical and/or electronic control means shown generally as counter/register unit 12, clutch control 14, and carriage return control unit 16.

The mechanical unit 10 includes an electric motor 20 to which a font wheel mounting and rotating shaft 22 is operatively coupled at one end thereof for continuous rotation when the motor is energized. A toothed pulley 21 is operatively coupled to the opposite end of the motor for transmitting continuous rotative power to a one-revolution clutch 24.

A carriage drive member or screw member 26 is suitably mounted for rotation about an axis parallel to the axis of shaft 22. The right-hand end of screw member 26 is coupled to an output shaft of one-revolution clutch 24. The input shaft 28 of the one-revolution clutch has attached thereto a toothed pulley 30. Interconnecting means, shown as toothed belt 32 provides for continuous synchronous rotation of the input shaft 28 of the clutch with respect to rotation of the shaft 22. The synchronous relationship between rotation of shaft 22 and input shaft 28 is a one-to-one relationship in this described embodiment. However, it will be apparentthat other ratios may be provided that are compatible with the operating requirements of the remainder of the structural elements to be described below.

Upon triggering of the one-revolution clutch 24, the screw member 26 will be caused to make one complete revolution. However, the angular speed of the screw member 26 during its one revolution varies, the best demonstrated in FIG. 3, due to the fact that it takes time to accelerate the screw from zero angular velocity to its maximum constant angular velocity, and to decelerate the screw from its maximum constant angular velocity back to zero velocity.

As demonstrated in FIG. 3, acceleration takes place from to about 90 during one cycle of operation, constant velocity occurs from about 90 to about 270 of an operation cycle, and deceleration takes place from about 270 to 360 of the operation cycle. The varying angular velocity portions of the rotation of the screw member 26 effect a varying lateral velocity of the continuously rotatable-type font wheel 34 as described more fully below. I

The screw member 26 is formed with a helical groove 36 having a predetermined pitch, which is shown by dimension arrow 38 (FIG. 2), helix angle or slope 40 (FIG. 2), and sense which is that of a right-handed screw.

A carriage 42 is suitably mounted for reciprocal movement in a path of travel parallel with the axes of rotation of shaft 22 and screw member 26. The lower forward portion 44 of the carriage is in surrounding relation with a portion of the screw member 26. A solenoid actuated carriage drive pin 46 is mounted in the lower portion of the carriage for reciprocal movement into and out of a portion of groove 36 that passes through the screw surrounding forward carriage portion 44. It will be understood that with the screw member 26 rotating clockwise about its axis, as indicated by direction arrow 48, and drive pin 46 engaged within groove 36, the carriage 42 will be driven from left-to-right (as viewed in FIGS. 1 and 2) which is the normal printing direction for the described embodiment.

A biasing means, such as a spring 50 normally biases the carriage 42 in the leftward direction. Thus, when the drive pin 46 is retracted from engagement with the groove 36 by energization of drive pin solenoid 51, the carriage will be returned to its leftward or home position.

The shaft 22 is, in cross section, square shaped. A circular or disclike font wheel 34 is mounted on the shaft 22 such that the font wheel rotates the shaft and is slidable axially along the shaft.

A yokelike font wheel translating member 52 is secured to the carriage 42 and extends upward into engagement with a narrow groove 54 (shown best in FIG. 2) on one side of the font wheel. Thus, as the carriage 42 is moved back and forth as described above, the yoke member acts on the font wheel to cause a like amount of movement or translation in a path of travel parallel with the axes of rotation of the shaft 22 and screw member 26.

The radially outer periphery 56 of the font wheel 34 contains a plurality of character or printing types 58 spaced thereabout in a sinuous pattern, which will be described in more detail below, in connection with FIG. 2.

A print hammer support platform 60 is disposed rearwardly (as viewed in FIG. I) of the font wheel 34 and is secured to the carriage 42 by appropriate means such as U-shaped bracket 62, for movement with the carriage. A print hammer 64 and actuating solenoid 66 is mounted on the support platform. Upon electrical energization of the solenoid 66, the print hammer 64 is caused to rapidly move forward toward a location on the periphery of the font wheel.

Ordinarily, a sheet of paper 68 is positioned between the font wheel 34 and the print hammer 64. Thus, when the print hammer is energized, as mentioned above, it rapidly and firmly engages the rear side or surface of the paper and urges a small area of the front surface of the paper into firm engagement with a character type on the periphery of the font wheel. Ink contained on the character type (by means not shown here, but fully disclosed in the aforementioned U.S. application, Ser. No. 650,501) is thus transferred to the paper and a character is thus printed on the paper.

The particular character that is printed and its printing location on the paper will now be described. At the left end portion of the shaft 22, there is secured a character timing or identification wheel 70 which rotates with the shaft 22 and, of

course, rotates with the font wheel 34. Sensor means, shown as inductance coils 72 and 74 cooperate with character identification means shown as teeth 76 and tab 78 to transmit a set of electrical signals to the counter/register unit 12 and clutch control unit 14, which signals precisely define or identify the particular character type that is in printing position opposite the print hammer 64 as the shaft 22 is rotated. It will be apparent to one skilled in the art that there are various ways of identifying the character type on a rotational font wheel that is in printing position; for example, photoelectric sensors may be utilized in conjunction with a timing wheel. The toothed wheel 70 and inductance coils shown in FIG. 1 are illustrative only.

Sets of electrical character code signals or data indicative of the individual character to be printed in each printing position are furnished asynchronously from an input data source such as a typewriter keyboard (not shown) to the counter/register unit 12. The counter/register unit 12 includes a set of data detection gates which will transmit a data received signal over a lead 80 to the clutch control unit 14. The clutch control is conditioned by a data received signal on lead 80 to respond to the next indexing or home signal on a lead 82. The indexing or home signal is generated as the index or home tab 78 passes by the associated inductance coil 74. The clutch control responds to the presence of the above-mentioned signal on leads 80 and 82 by transmitting an electrical clutch operate and counter/register count-enable signal via a lead 84 to the one-revolution clutch 24 and the counter/register unit 12.

The clutch 24 responds to the signal on lead 84 by causing power from continuously rotating pulley 30 to be coupled to screw member 26 for a period of time necessary to effect one revolution only of the screw member. The one-revolution of the screw member takes place with a velocity pattern described previously and shown in FIG. 3. This one-revolution of the screw member effects lateral movement of the carriage 42 and axial movement of the font wheel 34 one column or print position to the right, as viewed in FIGS. 1 and 2, with a velocity pattern like that described for the screw member and also shown in FIG. 3. The font wheel is moved axially from left to right across the paper 68 by a distance equal to the pitch 38 of the screw member as the screw member makes one revolution, as described above.

The counter/register unit 12 is also conditioned by the aforementioned electrical signal on lead 84 for accepting and counting in a decreasing or increasing mode, as desired, as will be apparent to those skilled in the art to which the present invention pertains, the series of character type representative signals generated in inductance coil 72 and transmitted via lead 86. When the counter/register is counted down (or up) to zero contents, an electrical character type print signal is generated in the counter/register unit and transmitted via lead 88 to the print hammer solenoid 66. The pring hammer solenoid is energized, thereby driving the print hammer forward to press the paper 68 into firm rapid engagement with the one selected print character type 58 that is in printing position 91 (FIG. 2) at the time.

A new set of character input data may then be furnished from the input data source at some later asynchronous time for printing the next character.

The character types 58 are disposed on the font wheel's periphery 56 in a modified helical arrangement best described as sinuous, as shown in FIG. 2. In FIG. 2, the periphery 56 of the font wheel is shown in dotted lines 56a as it would appear if it were unrolled" and laid out flat. Then the observer is looking at the periphery in the direction radially outward from the center of the wheel; this is for the purpose of more readily showing the principles of the present invention.

The individual character types 58 are offset axially from adjacent character types by predetermined amounts not all equal. The arrangement or pattern of axial offsetting is in a sinuous manner to compensate for the variable velocity pattern or lateral translation of the font wheel as it is moved one column space during printing operation of each character.

Each of the character types 58 are spaced circumferentially from adjacent types by equal angles or distances. Thus, with the 20 character types shown by way of example in FIG. 2, the character types 58 are each spaced 18 from adjacent character types. It will be apparent that any desired number of character types may be disposed about the circumference of the font wheel and spaced from adjacent types by the appropriate distance or angle.

However, as shown in FIG. 4, the lateral displacement of the font wheel during rightward movement of one revolution (360) of the font wheel is not a constant or straight-line function of the angular movement of the font wheel. For example, during the acceleration phase which extends from to about 90, the lateral displacement of the font wheel is not as great for a unit angular change in rotation of the font wheel as the lateral displacement that takes place per unit angular movement of the font wheel during the constant velocity lateral movement phase which extends from about 90 to about 270. A like situation occurs in the deceleration phase which extends from about 270 to 360. As shown in FIG. 4, the chart or graph of the lateral displacement of the font wheel appears sinuous. Thus, it will be apparent that in order to provide that each character type 58 be located at the same printing position 91 during an entire single constant velocity rotation of the font wheel as it is moved laterally one column space 38 with a varying velocity as shown in FIG. 3, the characters 58 must be arranged axially about the font wheel so as to compensate for such varying lateral displacement. Such compensating pattern or arrangement is sinuous as shown in FIG. 2 and such sinuous arrangement is directly related to the sinuous graph of FIG. 4.

Thus, it will be understood that rotation of the font wheel 34 through 360 will result in placement of successive ones of the character types 58 at the same printing location 91.

F tom the foregoing, it will be apparent that printing of the next character, defined by the next set of data signals received in counter/register 12, will cause printing of such next successive character in a new printing location to the right of the former printing location. Such successive printing locations are, of course, spaced by distance equal to space 38. When the extreme right-hand end of a printing line is reached, the carriage return control 16 recognizes such fact as, for example, by actuation of a microswitch (not shown) and generates a signal over lead 92, thereby energizing solenoid 51, pulling pin 46 out of engagement with helical groove 36 of screw member 26, thus permitting the force of spring 50 to return the carriage 42 to the extreme left position. Further, advancing means may be included to move the paper 68 upwardly or downwardly, if desired, one printing line. When the carriage 42 returns to its leftmost position, the carriage return control appropriately recognizes such fact and deenergizes solenoid 51, thereby permitting pin 46 to be once again engaged with the helical groove 36 of screw member 26. Other appropriate means for returning the carriage may be utilized as will be apparent to those skilled in the art to which the present invention pertains.

From the foregoing description, it will be apparent that the present invention provides for printing of equally spaced characters by means of a continuously rotating font wheel having a varying velocity lateral movement where the information or data signals are available in an asynchronous or nonregular mode. What I claim is: 1. An apparatus for printing characters on a surface of a print receiving medium, said apparatus comprising:

a font member having a substantially circular periphery and a plurality of character types disposed on said periphery, said font member being mounted for rotation about an axis, said types being equiangularly disposed from adjacent types about said axis;

means for continuously rotating said font member about said axis with a substantially constant angular velocity;

translating means for moving said font member axially along said axis a predetermined interval for each character to be printed with a compound velocity during each said interval, said compound velocity comprising an initial portion of increasing magnitude, an intermediate portion of substantially constant magnitude and a terminal portion of decreasing magnitude; and

control means for initiating operation of said translating means at the beginning of each said interval at a predetermined angular position of said font member; the axial spacing of successive ones of said character types about said periphery of said font member being matched to the corresponding axial displacement of said font member per angular rotational displacement thereof so that each of said character types passes adjacent a l predetermined point on said print receiving medium as said font wheel rotates and is moved axially during each said interval.

2. An apparatus according to claim 1 wherein there is further included first means for receiving a set of character indicative signals representative of selected ones of said character types on said font member; and

second means responsive to the receipt of a set of character indicative signals in said first means for initiating operation of said translating means at a predetermined angular position of said font member.

3. An apparatus according to claim 2 wherein said first means comprises a counter/register means for receiving a first set of character indicative signals at any time during rotation of said font member, said counter/register means generating a character received signal in response to receipt of said set of character indicative signals; and wherein said second means comprises means for generating a position indicative signal when said font member first rotates to said predetermined angular position subsequent to receipt of a set of character indicative signals in said counter/register means, and means responsive to the presence of both said character received signals and said position indicative signals for generating a translating means operating signal.

4. A printing apparatus according to claim 3 wherein there is further included third means for urging said print receiving medium and selective ones of said character types into printing engagement with each other while said font member is being rotated about said axis and moved axially;

said third means comprising means for generating a set of successive character-type representative signals as said font member rotates, successive ones of said charactertype representative signals being indicative of an associated one of said character types of said font member being in operative printing position; and

means responsive to the occurrence of the character-type representative signal representing the character type on said font wheel that corresponds to the character represented by said first set of character indicative signals received in said counter/register means for effecting printing engagement between said print receiving medium and the character type in printing position.

5. The apparatus according to claim 1 wherein said translating means includes:

a screw means having a helical groove provided therein,

said helical groove having a predetermined sense;

means for rotating said screw means in synchronism with rotation of said font member according to a predetermined ratio; and

means extending between said font member and said screw means for releasable engagement with said screw means, said releasable engagement means moving said font member in a first direction along said axis when in engagement with said screw means.

6. The apparatus of claim 5 wherein said means for rotating said screw includes a one revolution clutch.

7. The apparatus of claim 1 wherein said initial portion, said intermediate portion, and said terminal portion of said compound velocity each corresponds substantially to the 090, 75 90-270, and 270360 portion, respectively, of the rotational cycle of said font member, relative to said predeterat the end ofsaid terminal portion is substantially zero. mined angular position thereof. 9. The apparatus of claim 1 further including means for 8. The apparatus of claim 1 wherein the magnitude of said positioning said font member at an initial character print locacompound velocity at the beginning of said initial portion and tion prior to the operation ofsaid translating means. 

1. An apparatus for printing characters on a surface of a print receiving medium, said apparatus comprising: a font member having a substantially circular periphery and a plurality of character types disposed on said periphery, said font member being mounted for rotation about an axis, said types being equiangularly disposed from adjacent types about said axis; means for continuously rotating said font member about said axis with a substantially constant angular velocity; translating means for moving said font member axially along said axis a predetermined interval for each character to be printed with a compound velocity during each said interval, said compound velocity comprising an initial portion of increasing magnitude, an intermediate portion of substantially constant magnitude and a terminal portion of decreasing magnitude; and control means for initiating operation of said translating means at the beginning of each said interval at a predetermined angular position of said font member; the axial spacing of successive ones of said character types about said periphery of said font member being matched to the corresponding axial displacement of said font member per angular rotational displacement thereof so that each of said character types passes adjacent a predetermined point on said print receiving medium as said font wheel rotates and is moved axially during each said interval.
 2. An apparatus according to claim 1 wherein there is further included first means for receiving a set of character indicative signals representative of selected ones of said character types on said font member; and second means responsive to the receipt of a set of character indicative signals in said first means for initiating operation of said translating means at a predetermined angular position of said font member.
 3. An apparatus according to claim 2 wherein said first means comprises a counter/register means for receiving a first set of character indicative signals at any time during rotation of said font member, said counter/register means generating a character received signal in response to receipt of said set of character indicative signals; and wherein said second means comprises means for generating a position indicative signal when said font member first rotates to said predetermined angular position subsequent to receipt of a set of character indicative signals in said Counter/register means, and means responsive to the presence of both said character received signals and said position indicative signals for generating a translating means operating signal.
 4. A printing apparatus according to claim 3 wherein there is further included third means for urging said print receiving medium and selective ones of said character types into printing engagement with each other while said font member is being rotated about said axis and moved axially; said third means comprising means for generating a set of successive character-type representative signals as said font member rotates, successive ones of said character-type representative signals being indicative of an associated one of said character types of said font member being in operative printing position; and means responsive to the occurrence of the character-type representative signal representing the character type on said font wheel that corresponds to the character represented by said first set of character indicative signals received in said counter/register means for effecting printing engagement between said print receiving medium and the character type in printing position.
 5. The apparatus according to claim 1 wherein said translating means includes: a screw means having a helical groove provided therein, said helical groove having a predetermined sense; means for rotating said screw means in synchronism with rotation of said font member according to a predetermined ratio; and means extending between said font member and said screw means for releasable engagement with said screw means, said releasable engagement means moving said font member in a first direction along said axis when in engagement with said screw means.
 6. The apparatus of claim 5 wherein said means for rotating said screw includes a one revolution clutch.
 7. The apparatus of claim 1 wherein said initial portion, said intermediate portion, and said terminal portion of said compound velocity each corresponds substantially to the 0*-90*, 90*-270*, and 270*-360* portion, respectively, of the rotational cycle of said font member, relative to said predetermined angular position thereof.
 8. The apparatus of claim 1 wherein the magnitude of said compound velocity at the beginning of said initial portion and at the end of said terminal portion is substantially zero.
 9. The apparatus of claim 1 further including means for positioning said font member at an initial character print location prior to the operation of said translating means. 